The invention relates to the field of computers, and more specifically to the field of dynamically attachable buses for computer peripherals or devices.
Computer peripherals or devices are often connected to the computer through specific dedicated busesxe2x80x94such as the LPT parallel port bus or the COM serial bus generally found on personal computers. This type of connection induces limitations on the use of the device, due to the limited performance of the specific buses, and to the fact that they are dedicated to a limited number of tasks or products. The same applies to other personal computer""s input/output interfaces, such as the dedicated keyboard, mouse, and joystick interfaces.
Peripherals may also be connected to the computer with the help of a proprietary card that is inserted in the computer. In this case, communication between the card and the peripheral may follow a proprietary protocol, and is not prone to the limitations mentioned above. The drawback of such systems is that they make it necessary to open the computer casing for installing the card. In addition, the number of card slots in a given type of computer is limited.
Such interfaces do not provide plug and play functionality; in other words, installation of a peripheral involves either opening the computer for installing a dedicated card, or at least installing a specific driver. In addition, the fact that existing interfaces are dedicated to one or two specific products makes it necessary to develop a new interface any time a new product appears.
Recent buses, such as the USB (Universal Serial Bus) or the 1394 bus, propose plug and play and high capacity features. More details on USB may be found in the document Universal Serial Bus Specification. 1394 is developed under the IEEE by the 1394 Trade Association, and information on this bus may be found on the Internet Web site 1394TA.org.
These buses provide links that may be used across a wide range of PC to telephone applications. They provide the user with ease of use. They are also adapted to receive any type of peripherals, and not only a limited number of specific types of devices. In addition, they provide the user with a dynamically attachable interface, that allows any type of device to be plugged on the computer, or unplugged from the computer at any time, even when the computer is operating (xe2x80x9chot plug and playxe2x80x9d).
These new buses create new problems. One of the new problems addressed by the invention is the problem of theft of peripherals. Indeed, peripherals usable on a hot plug and play bus operate as soon as they are plugged on the corresponding bus, and are otherwise self supported; they do not need another componentxe2x80x94such as a specific card or driverxe2x80x94to be usable. In this respect, theft of a peripheral provides the thief with a device that is directly usable on the same type of bus on another computer.
Therefore, there is a need for a method for discouraging theft of peripherals and especially of peripherals or devices usable on buses of the hot plug and play type. This is all the more important since the total cost of a device usable on such buses comprises the cost of the device itself, there being no card in the computer.
According to the invention, there is provided a device for connection to a computer bus, with
means for storing information as to the owner of the device;
means for comparing the owner information stored with owner information received from computer on the bus, and
for restricting the operation of the device according to the result of the comparison.
In one embodiment of the invention, the restricting means restrict the operation of the device when the owner information received from the computer differs from owner information stored in said owner storing means.
According to a feature of the invention, the device may further comprise means for storing state information representative of a locked or unlocked state of the device.
In this case, the restricting means may restrict the operation of the device only when the state storing means store state information representative of a locked state of the device.
According to another feature of the invention, the comparing means may store in said state storing means state information received from the computer when the owner information received from the computer is identical to owner information stored in said owner storing means. The invention also provides a computer, with a bus for connecting devices, said computer comprising filter driver means for sending to a device plugged on the bus information representative of the owner of the computer. In one embodiment of the invention, said filter driver means sends said information at boot of the computer. Preferably, the bus allows dynamic device attaching, and the filter driver means sends said information when a device is attached to the bus.
In another embodiment of the invention, the filter driver means further sends to a device plugged on the bus information regarding a locking state of the device.
Preferably, the filter driver means send device unlocking information when logical removal of said device from the bus is inputted to the computer.